/Engine/Source/Runtime/AudioMixer/Public/Quartz/AudioMixerClockManager.h
Cancel a queued command on a clock (i.e. cancel a PlayQuantized command if the sound is stopped before it is played)
bool CancelCommandOnClock ( [FName](API\Runtime\Core\UObject\FName) InOwningClockName, [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [IQuartzQuantizedCommand](API\Runtime\Engine\Sound\IQuartzQuantizedCommand) > InCommandPtr )